The broad, long-term objective of the proposed research is to improve the ability to care for patients with heart failure, by providing better means to evaluate their heart function with magnetic resonance imaging (MRI) studies. MRI is a powerful medical imaging method, with a growing role in the care of heart patients. However, it has still been relatively little applied to the evaluation of diastole, the relaxation phase of the cardiac cycle, which can be affected before systole, the more commonly evaluated contraction phase of the cardiac cycle. The Specific Aims of the proposed research are to: 1) further develop technical methods for evaluation of diastole through tracking the motion of the atrioventricular junction, and 2) evaluate these methods in a sample of patients with heart failure and diastolic dysfunction and in matched control subjects. If successful, the proposed research has the potential to provide an improved means to assess diastolic function with MRI, which would be useful in caring for many patients who have or are at risk for developing heart failure.